When Untamed cards were released within a week I found Opportunity ability being my favorite ability out of all the ones that allows monsters to attack besides being in the front position. The main reasons I prefer opportunity over sneak and reach is that opportunity focuses on attacking weakest opponent for instant kill while not required to be at the front of formation. Almost like stealth kill ability. So cool! Here is a battle where I used a Serpentine Spy that has the opportunity ability.
The battle limited with 23 mana and had the abilities target practice and lost legends. In addition since water and life splinters were not allow in the match the next best formation I had was fire. It turned out to be a wise choice as my opponent used earth splinter which gave my fire splinter a slight advantage.
My Opponent's Formation
The Battle Results
The battle was quick and my Serpentine Spy played a key role in winning the match. Basically the Spy knocked out Brownie and finished off a couple of my opponent's monster. On my end only Ettin Spearman was knocked out and even that monster was able to withstand a couple rounds of attacks. If you are interested in watching the match here is a link..